Changing ink, in order to change color, ink composition or the like, in ink troughs of various types of printing machines is usually quite time-consuming. The ink troughs must be cleaned meticulously either while installed in the machine, or the ink troughs have to be disassembled, together with the applicable doctor blade and its adjustment mechanism from the machine. Otherwise, tipping the ink trough for emptying the same is also difficult since it is not easy to avoid spillage of ink and hence soiling the machine. Ink troughs or fountain systems having a portion which can be tipped are described, for example, in German Published Patent Applications DE-AS No. 22 30 126 and DE-AS No. 26 29 331.